<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>01_JS的三种引入方式</title>
    <script src="01.js">
        console.log('我我是外部js')
    </script>
</head>
<body>
    <button onclick="alert('请先登录')">点击登录</button>
    <button onclick="console.log('点我干嘛')">点wo</button>

    <h1 id="aaa">我是一级标题</h1>
    <script>
        console.log('我我是内部js')
        console.log(aaa)
    </script>
</body>
</html>